Surface mounting has become a preferred technique for circuit board assembly. As a consequence, virtually all types of electronic components have been or are being redesigned for surface mount (i.e., leadless) embodiments or applications. The rapid incorporation of surface mount devices (SMD) into all types of electronic circuits has created a corresponding need for SMD fuses.
Fuses serve an essential function on many circuit boards. By fusing a circuit, selected sub-circuits and/or even certain individual components, it is possible to prevent damage to an entire system which may otherwise result from failure of a single, local component.
There are many different performance characteristics of electrical components for which improvement may be sought to facilitate desired operation. A prior example of technology that addresses certain fuse aspects is disclosed in U.S. Pat. No. 7,570,148 to Parker et al. The Parker et al. patent concerns a low resistance fuse including a fuse element layer and first and second intermediate insulation layers extending on opposite sides of the fuse element layer and coupled thereto. The fuse element layer is formed on the first intermediate insulation layer and the second insulation layer is laminated to the fuse element layer. Another example is U.S. Pat. No. 5,296,833 (Breen et al.). Breen et al. concerns a surface mount fuse device including an alumina-glass-fuse-glass-alumina laminated structure.
Additional references that disclose exemplary technology with aspects of fuse design include U.S. Pat. Nos. 5,228,188, and 5,166,656 both to Badihi et al. Such Badihi et al. references generally concern surface mount fuses and methods for making the same.
The disclosures of all the foregoing United States patent documents are hereby fully incorporated herein for all purposes by reference thereto. It will be noted that none of the prior art publications addresses the need to provide surface mountable fuses rated for milli currents of about 50 milli-amps. Preferred embodiments address this need in packages smaller than 80 mil×50 mil (about 2 mm×1.5 mm), and sometimes as small as 40 mil×20 mil (about 1 mm×0.5 mm).